c语言实现编程实现请求分页存储管理页面Optimal、FIFO、LRU置换算法

好的，下面是C语言实现请求分页存储管理页面Optimal、FIFO、LRU置换算法的代码示例：

1. Optimal算法

#include <stdio.h>

int optimal(int pages[], int n, int frames) {
    int page_faults = 0;
    int page_frames[frames];
    int next_use[frames];
    
    for (int i = 0; i < frames; i++) {
        page_frames[i] = -1;
        next_use[i] = n;
    }
        
    for (int i = 0; i < n; i++) {
        int j;
        for (j = 0; j < frames; j++) {
            if (page_frames[j] == pages[i]) {
                next_use[j] = i;
                break;
            }
        }
        if (j == frames) {
            int farthest = 0;
            for (int k = 1; k < frames; k++) {
                if (next_use[k] > next_use[farthest])
                    farthest = k;
            }
            page_frames[farthest] = pages[i];
            next_use[farthest] = i;
            page_faults++;
        }
    }
    
    return page_faults;
}

int main() {
    int pages[] = { 1, 3, 0, 3, 5, 6, 3 };
    int n = sizeof(pages)/sizeof(pages[0]);
    int frames = 3;
    int page_faults = optimal(pages, n, frames);
    printf("Optimal: %d\n", page_faults);
    return 0;
}

2. FIFO算法

#include <stdio.h>

int fifo(int pages[], int n, int frames) {
    int page_faults = 0;
    int page_frames[frames];
    int queue[frames];
    int front = 0, rear = 0;
    
    for (int i = 0; i < frames; i++) {
        page_frames[i] = -1;
        queue[i] = -1;
    }
        
    for (int i = 0; i < n; i++) {
        int j;
        for (j = 0; j < frames; j++) {
            if (page_frames[j] == pages[i])
                break;
        }
        if (j == frames) {
            if (page_frames[rear] != -1) {
                int old_page = queue[front++];
                front %= frames;
                for (int k = 0; k < frames; k++) {
                    if (page_frames[k] == old_page) {
                        page_frames[k] = pages[i];
                        break;
                    }
                }
            }
            else {
                page_frames[rear++] = pages[i];
                rear %= frames;
            }
            queue[rear] = pages[i];
            page_faults++;
        }
    }
    
    return page_faults;
}

int main() {
    int pages[] = { 1, 3, 0, 3, 5, 6, 3 };
    int n = sizeof(pages)/sizeof(pages[0]);
    int frames = 3;
    int page_faults = fifo(pages, n, frames);
    printf("FIFO: %d\n", page_faults);
    return 0;
}

3. LRU算法

#include <stdio.h>

int lru(int pages[], int n, int frames) {
    int page_faults = 0;
    int page_frames[frames];
    int next_use[frames];
    
    for (int i = 0; i < frames; i++) {
        page_frames[i] = -1;
        next_use[i] = n;
    }
        
    for (int i = 0; i < n; i++) {
        int j;
        for (j = 0; j < frames; j++) {
            if (page_frames[j] == pages[i]) {
                next_use[j] = i;
                break;
            }
        }
        if (j == frames) {
            int farthest = 0;
            for (int k = 1; k < frames; k++) {
                if (next_use[k] > next_use[farthest])
                    farthest = k;
            }
            page_frames[farthest] = pages[i];
            next_use[farthest] = i;
            page_faults++;
        }
    }
    
    return page_faults;
}

int main() {
    int pages[] = { 1, 3, 0, 3, 5, 6, 3 };
    int n = sizeof(pages)/sizeof(pages[0]);
    int frames = 3;
    int page_faults = lru(pages, n, frames);
    printf("LRU: %d\n", page_faults);
    return 0;
}

以上是C语言实现请求分页存储管理页面Optimal、FIFO、LRU置换算法的代码示例。